This invention relates to a control device for an automatic transmission which is made switchable between automatic mode and manual mode by manual operation.
Among automatic transmissions, there is a type which allows manual switching between automatic mode, in which gear-shifting operation is performed according to preset shifting characteristics, and manual mode, in which gear-shifting operation is manually performed by a driver, in a drive range (refer to Japanese Unexamined Patent Publication No. 2-125174). When the transmission has been switched to the manual mode, gear setting which has been accomplished immediately before switching to the manual mode is usually maintained unless a shift is made in the manual mode thereafter.
Also among the automatic transmissions, there is a type in which the transmission is once set to a specific high-speed gear (e.g., third speed gear) other than first speed gear and then set to the first speed gear, instead of promptly setting to the first speed gear, to prevent or reduce shocks when gears have been changed from a non-drive range to a drive range to start off (Japanese Unexamined Patent Publication No. 61-065949).
It is considered feasible to combine the aforementioned two techniques such that the transmission can be manually switched between the automatic mode and the manual mode and set to first speed gear after once accomplishing a specific high-speed gear setting when gears have been changed from a non-drive range to a drive range.
Assuming that such a combination has been made, a certain driver may switch an automatic transmission to the manual mode immediately after switching it from a non-drive range to a drive range on some occasions. In such a case, the driver would think that the automatic transmission has been set to the first speed gear when switched to the drive range because his or her vehicle is now starting off, and later manual shifting would be made on the assumption that the current gear setting is the first speed gear.
If, however, the transmission is switched to the manual mode while it is in a specific high-speed gear selected when the transmission has been switched to the drive range, and the gear setting accomplished immediately before switching to the manual mode is maintained, the gear setting thus maintained would be the aforementioned specific high-speed gear and this would cause a loss of opportunity to accomplish the first speed gear by way of the specific high-speed gear. In addition, the driver might perform manual operation based on a misunderstanding that the transmission is currently maintained at the first speed gear despite the fact that it is actually
The present invention has been made in consideration of the aforementioned situations, and its object is to provide a control device for an automatic transmission which can avoid such a situation that the transmission, which is designed to be set to first speed gear after it has once been set to a specific high-speed gear when switched to a drive range, is maintained at the specific high-speed gear when the transmission is switched to manual mode while it is in the specific high-speed gear.
According to the invention, a control device for an automatic transmission which is made manually switchable between automatic mode, in which gear-shifting operation is performed according to preset shifting characteristics, and manual mode, in which gear-shifting operation is manually performed by a driver, in a drive range comprises temporary high-speed gear setting means which causes the automatic transmission to accomplish first-speed gear after it has once been set to a specific high-speed gear other than first speed gear when switched from a non-drive range to the drive range, and priority means which gives priority to accomplishment of the first-speed gear by the aforementioned temporary high-speed gear setting means when the automatic transmission is switched to the aforementioned manual mode while it is set to the aforementioned specific high-speed gear by the aforementioned temporary high-speed gear setting means.